Metridium Anemones

Anemones
are part of the Phylum Cnidaria, along with jellyfish and corals. Cnidarians
have two body forms, one free-swimming, called a medusa, and the other is
stationary and called a polyp. Jellyfish have the medusoid body form, with a
bell-shaped body and tentacles along the edge of the bell. A polyp such as a sea
anemone is essentially a jellyfish turned on its head, with its body more
tube-shaped and the tentacles directed upwards into the water column

Most
sea anemones are predaceous, immobilizing their prey with the aid of specialized
stinging cells called nematocysts. Metridium Giganteum is the species that we
are most familiar with as Pacific Northwest Divers. This large, fluffy white
anemone is found throughout the region attached to docks, pilings and other hard
substrate. It can also be found in colors ranging from orange to a brown or tan
color.

Like other
animals in the phylum Cnidaria, plumose anemones feed on small plankton
(drifting animals and plants), that they capture with their stinging cells.
They, in turn, are eaten by several different kinds of animals, including the
nudibranch, Aeolidia papillosa, and the Leather star (Dermasterias imbricata.)

Metridium
Anemones have been observed reproducing by “cloning”, where the animal actually
splits in two to form two identical Polyps. Individual animals can live to be
several centuries old, and have lived nearly 100 years in aquariums before dying
due to equipment malfunction ( not old age ). Scientific studies have shown
that the size of an adult Anemone is closely related to the speed of the
current. They feed most efficiently from the eddies created by the current
flowing over the back of their head, with larger animals more predominate in
moderate currents.